The invention relates generally to power converter systems and more specifically to a method and system for operating a power converter system in a normal mode and a failure mode.
Many devices, such as power supply systems, include power converter systems. A power converter system is typically used to convert an input voltage, which may be fixed frequency, variable frequency, or dc to a desired converter output voltage. The output voltage and frequency may be fixed or variable. A converter system usually includes several switches such as insulated gate bipolar transistors (IGBTs) that are switched at certain frequencies to generate the desired converter output voltage and frequency. The converter output voltage is then provided to various loads via transformers. Loads as used herein are intended to broadly include motors, power grids, and resistive loads, for example.
In several applications such as wind power generation and industrial power generation, for example, power converter systems typically include several components like bridges and transformers. A single point failure in such converter systems may lead to the shutting down of the entire power converter system, thereby lowering availability. It is therefore desirable to design a power converter system with higher availability.
In a situation where a component in the power converter system fails, the converter output voltage is not of high quality. That is, the converter output voltage may include harmonic components. Thus, it is desirable to maintain harmonic components in the converter output voltage at a minimum level, even when a single point failure occurs.
Therefore, what is desired is a power converter system that is capable of operating when a component in the system fails while maintaining a high quality output voltage with minimum harmonic components.